1. Field of the Invention
This invention relates to novel 4D5 antibodies that specifically bind HER2/neu, and particularly novel chimeric 4D5 antibodies to HER2/neu, which have reduced glycosylation and altered effector functions as compared to known 4D5 antibodies. The invention also relates to methods of using the antibodies and compositions comprising them in the diagnosis, prognosis and therapy of diseases such as cancer, autoimmune diseases, inflammatory disorders, and infectious disease.
2. Description of the Related Art
HER2/neu and HER2/neu Receptors
Cellular growth and differentiation processes involve growth factors that exert their actions through specific receptors such as the tyrosine kinases. The binding of ligand to a tyrosine kinase receptor triggers a cascade of events that eventually lead to cellular proliferation and differentiation. (Carpenter et al. (1979) Biochem. 48:193-216; Sachs et al. (1987) Cancer Res. 47:1981-8196). Tyrosine kinase receptors can be classified into several groups on the basis of sequence similarity and distinct features. One such family is the ErbB or epidermal growth factor receptor family, which includes multiple receptors known as HER-1 (also known as erbB-1 or EGFR), HER-2 or HER2/neu (also known as erbB-2, c-neu, or p185), HER-3 (also known as erbB-3), and HER-4 (also known as erbB-4). (See, e.g., Carpenter et al., supra; Semba et al. (1985) Proc. Natl. Acad. Sci. (U.S.A.) 82: 6497-6501; Coussens et al. (1985) Science, 230:1130-1139, Bargmann et al. (1986) Cell 45:649-657; Kraus et al. (1989) PNAS 86: 9193-9197; Carraway et al. (1994) J. Biol. Chem. 269:14303-14306; and Plowman et al. (1993) Nature 366: 473-475; Tzahar et al. (1994) Biol. Chem. 269: 25226-25233).
The ErbB receptors play important roles in propagating signals regulating cell proliferation, differentiation, motility, and apoptosis, both in normal developmental processes and in human tumorigenesis. (Slamon et al. (1989) Science 244:707-712). For example, the activation of erbB receptors is coupled to and stimulates downstream MAPK-Erk1/2 and phosphoinositide-3-kinase (PI3K)/AKT growth and survival pathways. The deregulation of these pathways in cancer has been linked to disease progression and refractoriness to therapy. (Fukazawa et al. (1996) J. Biol. Chem. 271:14554-14559; Tzahar et al. (1996) Mol. Cell. Biol. 16:5276-5287; Lange et al. (1998) J. Biol. Chem. 273:31308-31316; Olayioye et al. (1998) Mol. Cell. Biol. 18:5042-5051; Hackel et al. (1999) Curr. Opin. Cell Biol. 11:184-189). Activation of PI3K/AKT promotes cell survival and enhanced tumor aggressiveness, and AKT2 was reported to be activated and overexpressed in HER2/neu-overexpressing breast cancers. (Shak (1999) Semin Oncol. Suppl 12:71-77; Huang et al. (2000) Clinical Cancer Res. 7:2166-2174; Bacus et al. (2002) Oncogene 21:3532-3540).
Signaling by the ErbB family of receptors is initiated by ligand binding which triggers homo- or hetero-receptor dimerization, reciprocal tyrosine phosphorylation of the cytoplasmic tails, and activation of intracellular signal transduction pathways. (Citri et al. (2003) Exp. Cell Res. 284:54). The availability of ligands that bind to and activate the ErbB receptors is mediated by various metalloproteases, such as the ADAM (A Disintegrin And Metalloprotease) family of zinc-dependent metalloproteases, which catalyze cell surface ectodomain shedding of specific proteins. (See Chang and Werb (2001) Trends in Cell Biology 11:537-543; Moss and Lambert (2002) Essays in Biochemistry 38:141-153; Seals and Courtneidge (2003) Genes and Development 17:7-30). Specifically, the ADAM family has been shown to cleave ligands responsible for activating the ErbB receptors, such as APP and Notch. (Blobel (2005) Nat. Rev. Mol. Cell. Biol. 6:32-43).
An important member of the ErbB family, HER2/neu, is a 185 kDa receptor protein that was originally identified as the product of the transforming gene from neuroblastomas of chemically treated rats. HER2/neu has been extensively investigated because of its role in several human carcinomas and in mammalian development. (Hynes and Stern (1994) Biochim et Biophys. Acta 1198:165-184; and Dougall et al. (1994) Oncogene 9:2109-2123; Lee et al. (1995) Nature 378:394-398). The human HER2/neu gene and HER2/neu protein are described in Semba et al. (1985) Proc. Natl. Acad. Sci. (U.S.A.) 82:6497-6501 and Yamamoto et al. (1986) Nature 319:230-234, and the sequence is available in GenBank as accession number X03363. HER2/neu comprises four domains: an extracellular domain to which ligand binds; a lipophilic transmembrane domain; a conserved intracellular tyrosine kinase domain; and a carboxyl-terminal signaling domain harboring several tyrosine residues that can be phosphorylated. (Plowman et al. (1993) Proc. Natl. Acad. Sci. (U.S.A.) 90:1746-1750). The sequence of the HER2/neu extracellular (ECD) domain was described by Franklin et al. (2004) Cancer Cell. 5(4):317-328, and is available in Protein DataBank Record 1S78 (2004).
HER2/neu functions as a growth factor receptor and is often expressed by tumors such as breast cancer, ovarian cancer and lung cancer. HER2/neu is overexpressed in 25-30% of human breast and ovarian cancers, and is associated with aggressive clinical progression and poor prognosis in these patients. (Slamon et al. (1987) Science 235:177-182; Slamon et al. (1989) Science 244:707-712). Overexpression of HER2/neu has also been observed in other carcinomas including carcinomas of the stomach, endometrium, salivary gland, lung, kidney, colon, thyroid, pancreas and bladder. (See, e.g., King et al. (1985) Science 229:974; McCann et al. (1990) Cancer 65:88-92; Yonemura et al. (1991) Cancer Research 51:1034).
Activation of HER2/neu has been correlated with reduced clinical responsiveness to hormone therapy in breast cancer patients. (Wright et. al. (1989) Cancer Res. 49:2087-2090; Kurokawa & Arteaga (2001) Clin. Cancer Res. 7:4436s-42s, 4411s-4412s). Indeed, HER2/neu expression is sufficient to convey anti-estrogen resistance. (Benz et. al. (1993) Breast Cancer Res. Treat. 24:85-95). HER2/neu, as well as HER-3, also appears to be involved in the onset of hormone resistance in prostate cancer patients. Approximately one-third of prostate cancer patients receive hormone therapy treatment aimed at disrupting the action of testicular and adrenal androgens. As with breast cancer, resistance is inevitable. Recent data suggests that signals emanating from HER2/neu and HER-3 induce a “hormone-refractory” state. (Mellinghoff et. al. (2004) Cancer Cell 6:517-527).
Several truncated and spliced versions of HER2/neu are known. For example, a truncated ECD located in the perinuclear cytoplasm of some gastric carcinoma cells is produced by an alternative transcript generated by use of a polyadenylation signal within an intron. (Yamamoto et al. (1986) Nature 319:230-234; and Scott et al. (1993) Mol. Cell. Biol. 13:2247-2257). No particular therapeutic, diagnostic or research utility has been ascribed to this truncated ECD polypeptide. The ECD of HER2/neu can also be proteolytically shed from breast carcinoma cells in culture, and is found in the serum of some cancer patients where it is may be a serum marker of metastatic breast cancer and overall poor prognosis. (Petch et al. (1990) Mol. Cell. Biol. 10:2973-2982; Leitzel et al. (1992) J. Clin. Oncol. 10:1436-1443; Scott et al. (1993) Mol. Cell. Biol. 13:2247-2257; and Lee and Maihle (1998) Oncogene 16:3243-3252). In some HER2/neu overexpressing tumor cells, 4-aminophenylmercuric acetate (APMA), a well-known metalloprotease activator, activates metalloproteases such as ADAM10 and ADAM15 to cleave the HER2/neu receptor into two parts: a truncated membrane-associated receptor known as p95, and a soluble ECD known as p105 or ECD105. (See, e.g., Molina et al. (2001) Cancer Res. 61:4744-4749; U.S. Patent Publication No. 2004/0247602). Loss of the ECD renders the p95 receptor a constitutively active tyrosine kinase, which can deliver growth and survival signals to cancer cells. (See, e.g., U.S. Pat. No. 6,541,214).
Studies have shown that in HER2/neu overexpressing breast cancer cells, treatment with antibodies specific to HER2/neu in combination with chemotherapeutic agents (e.g., cisplatin, doxoubicin, taxol) elicits a higher cytotoxic response than treatment with chemotherapy alone. (Hancock et al. (1991) Cancer Res. 51:4575-4580; Arteaga et al. (1994) Cancer 54:3758-3765; Pietras et al. (1994) Oncogene 9:1829-1838). One possible mechanism by which HER2/neu antibodies might enhance response to chemotherapeutic agents is through the modulation of HER2/neu protein expression or by interfering with DNA repair. (Stancovski et al. (1991) Proc. Natl. Acad. Sci. (U.S.A.) 88:8691-8695; Bacus et al. (1992) Cell Growth & Diff. 3:401-411; Bacus et al. (1993) Cancer Res. 53:5251-5261; Klapper et al. (1997) Oncogene 14:2099-2109; Klapper et al. (2000) Cancer Res. 60:3384-3388; Arteaga et al. (2001) J Clinical Oncology 19(18s):32s-40s).
A number of monoclonal antibodies and small molecule tyrosine kinase inhibitors targeting HER-1 or HER2/neu have been developed. For example, a murine monoclonal antibody known as 4D5 recognizes an extracellular epitope (amino acids 529 to 627) in the cysteine-rich II domain of HER2/neu that resides very close to the transmembrane region. Treatment of breast cancer cells with 4D5 partially blocks NDF/heregulin activation of HER2/neu-HER-3 complexes, as measured by receptor phosphorylation assays. (Carter et al. (1992) Proc. Natl. Acad. Sci. (U.S.A.) 89:4285-4289; Sliwkowski et al. (1999) Sem. in Oncol. 26:60-70; Ye et al. (1999) Oncogene 18:731-738; Vogel et al. (2001) Oncology 61(suppl 2):37-42; Vogel et al. (2002) Journal of Clinical Oncology 20(3):719-726; Fujimoto-Ouchi et al. (2002) Cancer Chemother. Pharmacol. 49:211-216). Administration of 4D5 to humans, however, was a clinical failure because patients quickly developed HAMA responses, so humanized forms were developed. The sequence and crystal structure of humanized antibody 4D5 have been described in U.S. Pat. No. 6,054,297, Carter et al., supra, and Eigenbrot et al. (1993) J. Mol. Biol. 229:969-95.
A humanized form of 4D5 known as trastuzumab (sold as Herceptin® by Genentech, Inc.) was developed and approved for treating cancers involving the overexpression or gene amplification of HER2/neu, including breast cancer. (Cobleigh et al. (1999) J. Clin. Oncol. 17:2639-2648). Trastuzumab inhibits the APMA-mediated cleavage of HER2/neu into the ECD and p95 portions in vitro, and is believed to work in vitro through different mechanisms, including the possible inhibition of HER2/neu shedding. (Pegram et al. (1998) Journal of Clinical Oncology 16(8):2659-2671; Baselga et al. (2001) Seminars in Oncology 28(5)(suppl. 16):4-11; Baselga et al. (2001) Annals of Oncology 12 (suppl. 1):535-541). Trastuzumab therapy has various drawbacks, however, such as cardiotoxicity and development of HAHA responses in some patients.
Thus, there is still a need for new or improved forms of HER2/neu antibodies for use in cancer therapies, for example 4D5 antibodies having increasing affinity or specificity, reduced potential for HAMA or HAHA responses, altered effector functions, and the like.
Fc Receptors
The interaction of antibody-antigen complexes with cells of the immune system results in a wide array of responses, ranging from effector functions such as antibody-dependent cytotoxicity, mast cell degranulation, and phagocytosis to immunomodulatory signals such as regulating lymphocyte proliferation and antibody secretion. All these interactions are initiated through the binding of the Fc domain of antibodies or immune complexes to Fc receptors, which are specialized cell surface receptors on hematopoietic cells. The diversity of cellular responses triggered by antibodies and immune complexes results from the structural heterogeneity of Fc receptors. Fc receptors share structurally related ligand binding domains which presumably mediate intracellular signaling.
The Fc receptors, members of the immunoglobulin gene superfamily of proteins, are surface glycoproteins that can bind the Fc portion of immunoglobulin molecules. Each member of the family recognizes immunoglobulins of one or more isotypes through a recognition domain on the a chain of the Fc receptor. Fc receptors are defined by their specificity for immunoglobulin subtypes. Fc receptors for IgG are referred to as “FcγR,” for IgE as “FER,” and for IgA as “FcαR.” Different accessory cells bear Fc receptors for antibodies of different isotype, and the isotype of the antibody determines which accessory cells will be engaged in a given response (Billadeau et al. (2002) J. Clin. Investigat. 2(109):161-81; Gerber et al. (2001) Microbes Infection 3:131-139; Ravetch et al. (2001) Annu. Rev. Immunol. 19:275-90; Ravetch et al. (2000) Science 290:84-89; Ravetch (1994) Cell 78(4):553-560; Ravetch et al. (1991) Annu. Rev. Immunol. 9:457-492; see also, Immunobiology: The Immune System in Health and Disease (4th ed. 1999), Elsevier Science Ltd/Garland Publishing, New York). An overview of various receptors is presented in Table 1.
TABLE 1Receptors for the Fc Regions of Immunoglobulin IsotypesReceptorBindingCell TypeEffect of LigationFcγRIIgG1MacrophagesUptake(CD64)108M−1NeutrophilsStimulationEosinophilsActivation of respiratory burstDendritic cellsInduction of killingFcγRII-AIgG1MacrophagesUptake(CD32)2 × 106M−1NeutrophilsGranule releaseEosinophilsDendritic cellsPlateletsLangerhan cellsFcγRII-B1IgG1B cellsNo uptake(CD32)2 × 106M−1Mast cellsInhibition of StimulationFcγRII-B2IgG1MacrophagesUptake(CD32)2 × 106M−1NeutrophilsInhibition of StimulationEosinophilsFcγRIIIIgG1NK cellsInduction of Killing(CD16)5 × 105M−1EosinophilsMacrophagesNeutrophilsMast CellsFcεRIIgEMast cellsSecretion of granules1010M−1EosinophilBasophilsFcαRIIgA1, IgA2MacrophagesUptake(CD89)107M−1NeutrophilsInduction of killingEosinophils
Each Fcγ receptor (“FcγR”) is an integral membrane glycoprotein, possessing extracellular domains related to a C2-set of immunoglobulin-related domains, a single membrane spanning domain and an intracytoplasmic domain of variable length. There are four known FcγRs, designated FcγRI (CD64), FcγRII (CD32), FcγRIII (CD16), and FcγRIV. The receptors are encoded by distinct genes; however, the extensive homology between the family members suggest they arose from a common progenitor perhaps by gene duplication.
Both activating and inhibitory signals are transduced through the FcγRs following ligation. These diametrically opposing functions result from structural differences among the different receptor isoforms. Two distinct domains within the cytoplasmic signaling domains of the receptor called immunoreceptor tyrosine based activation motifs (ITAMs) or immunoreceptor tyrosine based inhibitory motifs (ITIMS) account for the different responses. The recruitment of different cytoplasmic enzymes to these structures dictates the outcome of the FcγR-mediated cellular responses. ITAM-containing FcγR complexes include FcγRI, FcγRIIA, FcγRIIIA, and FcγRIV, whereas ITIM-containing complexes only include FcγRIIB.
FcγRI displays high affinity for the antibody constant region and restricted isotype specificity (Hulett and Hogarth (1994) Adv Immunol 57:1-127). FcγRII proteins are 40 KDa integral membrane glycoproteins which bind only the complexed IgG due to a low affinity for monomeric Ig (106 M-1). This receptor is the most widely expressed FcγR, present on all hematopoietic cells, including monocytes, macrophages, B cells, NK cells, neutrophils, mast cells, and platelets. FcγRII has only two immunoglobulin-like regions in its immunoglobulin binding chain and hence a much lower affinity for IgG than FcγRI. There are three known human FcγRII genes (FcγRII-A, FcγRII-B, FcγRII-C), all of which bind IgG in aggregates or immune complexes. Human neutrophils express the FcγRIIA gene. The FcγRIIB gene is expressed on B lymphocytes; its extracellular domain is 96% identical to FcγRIIA and binds IgG complexes in an indistinguishable manner.
Distinct differences within the cytoplasmic domains of FcγRII-A and FcγRII-B create two functionally heterogenous responses to receptor ligation. The FcγRII-A isoform initiates intracellular signaling leading to cell activation such as phagocytosis and respiratory burst, whereas the FcγRII-B isoform initiates inhibitory signals, e.g., inhibiting B-cell activation. FcγRIIA clustering via immune complexes or specific antibody cross-linking serves to aggregate ITAMs along with receptor-associated kinases which facilitate ITAM phosphorylation. ITAM phosphorylation serves as a docking site for Syk kinase, activation of which results in activation of downstream substrates (e.g., PI3K). Cellular activation leads to release of proinflammatory mediators. When co-ligated or co-aggregated along with an activating FcγR having an ITAM, such as FcγRIIA or FcεRI, the ITIM in FcγRIIB becomes phosphorylated and recruits the SH2 domain of the src homology 2-containing inositol phosphatase (SHIP), which in turn is phosphorylated and associates with Shc (Ott (2002) J. Immunol. 162(9):4430-4439; Yamanshi et al. (1997) Cell 88:205; Carpino et al. (1997) Cell 88:197). SHIP hydrolyzes phosphoinositol messengers released as a consequence of ITAM-containing FcγR-mediated tyrosine kinase activation, consequently preventing the influx of intracellular Ca++, and dampening cellular responsiveness to FcγR ligation. Thus, B cell activation, B cell proliferation and antibody secretion is aborted, and FcγR-mediated phagocytosis is down-regulated (Tridandapani et al. (2002) J. Biol. Chem. 277(7):5082-89).
Specifically, coaggregation of FcγRIIA with FcγRIIB results in down-regulation of phosphorylation of Akt, which is a serine-threonine kinase that is involved in cellular regulation and serves to suppress apoptosis, and coaggregation of FcγRIIB with the high affinity IgE receptor FcεRI in mast cells leads to inhibition of antigen-induced degranulation, calcium mobilization, and cytokine production (Long (1999) Annu Rev. Immunol 17:875; Metcalfe et al. (1997) Physiol. Rev. 77:1033). Coaggregation of FcγRIIB and the B-cell receptor (BCR) leads to inhibition of BCR-mediated signaling, and inhibition of cell cycle progression and cellular survival. Although numerous effector functions of FcγRIIB-mediated inhibition of BCR signaling are mediated through SHIP, recently it has been demonstrated that lipopolysaccharide (LPS)-activated B cells from SHIP deficient mice exhibit significant FcγRIIB-mediated inhibition of calcium mobilization, Ins(1,4,5)P3 production, and Erk and Akt phosphorylation (Brauweiler et al. (2001) Journal of Immunology 167(1): 204-211).
The size of FcγRIII ranges between 40 and 80 kDa in mouse and man, due to heterogeneity within this class. Two human genes encode two transcripts, FcγRIIIA, an integral membrane glycoprotein, and FcγRIIIB, a glycosylphosphatidyl-inositol (GPI)-linked version. One murine gene encodes an FcγRIII homologous to the membrane spanning human FcγRIIIA. The FcγRIII shares structural characteristics with each of the other two FcγRs. Like FcγRII, FcγRIII binds IgG with low affinity and contains the corresponding two extracellular Ig-like domains. FcγRIIIA is expressed in macrophages, mast cells, and is the lone FcγR in NK cells. The GPI-linked FcγRIIIB is currently known to be expressed only in human neutrophils.
FcγRIV (also known as mFcRIV) requires association of the FcR gamma-chain for optimal expression and function on myeloid cells; its signaling potential is also enhanced by a cytoplasmic “YEEP” motif that recruits the adaptor molecule Crk-L and phosphatidylinositol-3-OH kinase. FcγRIV preferentially binds immunoglobulin E antibodies of the b allotype (IgEb) as well as IgG2a and IgG2b antibodies. Ligation of FcγRIV by antigen-IgEb immune complexes promotes macrophage-mediated phagocytosis, presentation of antigen to T cells, production of proinflammatory cytokines and the late phase of cutaneous allergic reactions (Hirano et al. (2007) Nature Immunology 8:762-771). FcγRIV is a recently identified receptor, conserved in all mammalian species with intermediate affinity and restricted subclass specificity (Nimmerjahn et al. (2005) Immunity 23:41-51; Mechetina et al. (2002) Immunogenetics 54:463-468; Davis et al. (2002) Immunol Rev 190:23-36). FcRIII and FcRIV are physiologically important activation FcRs for mediating inflammatory disease triggered by cytotoxic antibodies or pathogenic immune complexes. FcRIV is found on dendritic cells, macrophages, monocytes and neutrophils.
Despite all such advances, a need remains for anti-HER2/neu antibodies that possess therapeutic use in the treatment of autoimmunity, cancer, inflammatory disease, and/or transplantation, and exhibit improved ability to mediate effector function from the Fc receptors. The present invention is directed to this and other needs.